FIG. 1 of the accompanying drawings shows, in highly diagrammatic form, certain major components of a typical desktop computer. In particular, within the casing 10 of the computer are shown the main printed circuit board 11 (motherboard) and the power supply unit 14; other major components such as storage devices have been omitted for clarity.
The motherboard 11 mounts a microprocessor chip 12, either directly (for example, by surface mounting) or by means of a socket. Modern microprocessor devices dissipate a substantial amount of heat during normal operation and typically operate at working temperatures of 70 to 85 degrees centigrade. For this reason it is often necessary with the more powerful microprocessors to take special measures to remove the dissipated heat. For example, and as depicted in FIG. 1, a heat sink 13 may be mounted on top of the microprocessor chip 12 in good thermal contact with it. Typically the heat sink comprises an array of fins (only diagrammatically indicated in FIG. 1); these fins facilitate the transfer of heat to the internal ambient air.
Of course, the main source of heat within a desktop computer as in most items of electronic equipment, is the power supply unit 14. In order to provide cooling to this unit, it is enclosed in a casing 15 that not only provides a safety barrier for high voltage protection, but also serves as a ducting through which a strong airflow can be passed to cool the electronic components of the unit 14. This air flow is created by a fan 16 located at one end of the ducting 15 and normally forming one subassembly together with the power supply unit 14. The fan 16 draws in air from internally of the computer casing 10 (this airflow is represented by arrows A in FIG. 1 and enters the fan through slot 17) and possibly also from externally of the casing 10 (airflow B). The air drawn in by the fan 16 is then forced through the ducting 15 and out of the casing 10 through external slot 18.
The reason for drawing in air through slot 17 from internally of the casing is that the resultant airflow A across the motherboard 11 facilitates the cooling of the components mounted on the motherboard 11 such as the microprocessor chip 12. However, the intensity of this airflow is much less than that passing through the ducting 15.
As the power of microprocessors continues to increase, the problem of dissipating the heat generated becomes more significant. One possible solution would be to use a more powerful fan and thereby increase the airflow past the microprocessor and its heat sink. However, this would result in a increase in noise level both from the fan itself and from the stronger airflow.
It is an object of the present invention to provide a convenient and cost effective way of improving heat removal from microprocessor and similar electronic components which does not require the use of a more powerful fan.